Equivalence Partitioning, also known as Equivalence Class Testing, is a powerful black-box testing technique designed to streamline testing by minimizing the number of test cases while ensuring comprehensive coverage.
This approach is widely used to make testing more efficient without sacrificing effectiveness. Let’s learn more about how it’s done!
Equivalence Class Testing is a black-box testing method where testers categorize input data into equivalence classes (or partitions). Each of these classes contain values that should be treated in the same way by the system.
Testers then select one or more representative values from each equivalence class for testing. Since these values should yield the same result as any other input in the class, this approach significantly reduces the need to test every possible input.
Equivalence partitioning is designed to minimize the number of test cases while maintaining thorough coverage.
Typically, testers categorize values into two primary classes:
To illustrate how equivalence class testing works, let's use a simple example. Suppose you're testing a function that validates a user's age for an online registration form, with a valid age range of 18 to 60 years.
Here’s how you could create equivalence classes:
Now, let's select representative values from each class:
From these, we can generate the following test cases:
To ensure you're creating effective equivalence classes, follow these key principles:
By adhering to these rules, you can reduce the number of test cases without compromising quality. While you may choose to create additional test cases, they usually won't uncover new issues. The main goal is to ensure broad test coverage while keeping the process manageable.
Although equivalence partitioning is efficient, there's always a risk of missing edge cases. For example, imagine the developers added a condition like:
if (age == "30")
then REJECT
This type of unexpected behavior could slip through unless you have access to the source code or receive specific guidance from the developers.
Equivalence Partitioning is ideal for systems with input ranges, where each value within a range is expected to behave similarly. To maximize its effectiveness, always confirm with the development team that the inputs within each equivalence class truly are equivalent.
Here are some scenarios where equivalence partitioning works well:
Equivalence Partitioning is a valuable testing technique that helps testers reduce the number of test cases without sacrificing quality.
Equivalence Class Partitioning (ECP) is a black-box testing technique that divides input data into groups (or partitions) with similar behavior. It is used to reduce the number of test cases while maintaining adequate coverage by testing one value from each group instead of testing all possible inputs.
To identify equivalence classes:
ECP focuses on grouping inputs into equivalent partitions, while BVA targets the values at the edges of these partitions. For example, if a valid input range is 1-100, ECP tests a representative value from the range, while BVA tests the edge values like 1 and 100.
Yes, ECP can be applied to non-numerical inputs like strings, dropdown selections, or file uploads. For example, if a dropdown menu has three options, each option represents a separate equivalence class.
By testing one representative value from each equivalence class, ECP eliminates the need to test every possible input, reducing redundancy. For instance, instead of testing all integers from 1-100, you can test just one value from the valid range and a few from invalid ranges.
ECP is typically used during the test design phase, especially for functional and system testing. It is most effective when the application has clearly defined input domains or ranges.
Yes, ECP is often combined with other techniques like Boundary Value Analysis (BVA) or Decision Table Testing to ensure comprehensive coverage of input domains and edge cases. For instance, you can use ECP for general partitioning and BVA to test the boundaries of those partitions.